Dissertation defence (Materials Engineering): MSc Hassan Ali Qureshi

MSc Hassan Ali Qureshi defends the dissertation in Materials Engineering titled “Microcavity engineering for scalable, efficient polaritonic applications” at the University of Turku on 21 April 2026 at 10.00 (University of Turku, Pub1 Mauno Koivisto lecture hall, Assistentinkatu 7, Turku).

Opponent: Associate Professor Grigorios Itskos (University of Cyprus, Cyprus)

Custos: Associate Professor Konstantinos Daskalakis (University of Turku)

Summary of the Doctoral Dissertation:

Light is something we use every day, from phone screens to lighting in our homes. But at a deeper level, light can also interact with materials in unusual and powerful ways. My doctoral research explores how light and matter can be combined to create new kinds of optical devices that are more efficient, scalable, and easier to manufacture.

In this work, I developed a new way to build tiny optical structures called microcavities using simple, solution-based methods—similar to techniques used in printing or coating. Traditionally, such structures require expensive and complex vacuum-based fabrication processes. By replacing these with more accessible methods, my research shows that it is possible to create high-quality optical devices in a more cost-effective and scalable way.

One of the key findings of my research is the demonstration of strong interaction between light and organic materials in these solution-processed structures. This interaction leads to the formation of new hybrid states, known as polaritons, which combine properties of both light and matter. I showed that these systems can even produce laser-like emission at room temperature, something that is typically difficult to achieve in organic materials.

In addition, my work reveals how carefully designing the structure of these microcavities allows us to control how light is emitted. This opens up new ways to improve devices such as organic light-emitting diodes (OLEDs), including the possibility of more efficient and color-stable lighting and displays.

The broader impact of this research lies in its potential to make advanced photonic technologies more practical and widely available. By simplifying fabrication and reducing costs, these findings could contribute to the next generation of energy-efficient displays, sensors, and optical communication technologies. Furthermore, the ability to control light–matter interaction at this level may enable new applications in quantum technologies and advanced materials.

Overall, this work bridges fundamental science and practical engineering, showing that complex optical phenomena can be harnessed using scalable and industry-relevant fabrication methods.